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WORLD INTELLECTUAL PROPERTY ORGANIZATION
International Bureau

PCT

INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

(51) International Patent
C01B 31/30

(11) International Publication Number: WO 96/29282

(43) International Publication Date: 26 September 1996 (26.09.96)

(21) International Application Number: PCT/US96V03257

(22) International Filing Date: 1 1 March 1996 (11.03.96)

(30) Priority Data:

407,556

20 March 1995 (20.03.95)

(71) Applicant: ARISTECH CHEMICAL CORPORATION

[US/US]; 600 Grant Street, Pittsburgh. PA 15219-2704
(US).

(72) Inventors: KELKAR, Chandrashekhar, P.; 17 Shangri-la

Circle, Pittsburgh, PA 15239 (US). SCHUTZ, Alain,
A.; 2301 Stonecliffe Drive, Monroeville, PA 15146 (US).
CULLO, Leonard, A.; Maplewood Terrace, 315 Maple
Drive, Greensburg, PA 15601 (US).

(74) Agent: GAVLIK, Robert, R.; Aristech Chemical Corporation,
Law Dept. 600 Grant Street, Pittsburgh, PA 15219-2704
(US).

(81) Designated States: CA. JP, European patent (AT, BE, CH, DE,
DK, ES. Fl FR, GB. GR, IE. IT, LU, MC. NL. PT, SE)

Published

With international search report.
Before the expiration of the time limit for amending the
claims and to be republished in the event of the receipt of
amendments.

(54) Title: NICKEL AND COBALT CONTAINING HYMOTALCITE-UKE MATERIALS HAVING A SHEET-LIKE MORPHOLOGY
AND PROCESS FOR PRODUCTION THEREOF

(57) Abstract

A synthetic nickel (or cobalt) containing hydrotalcite-like material having a sheet-like morphology and a sheet broadness to thickness
ratio of at least 50 and a formula M i AlxCOHh.xA.mH2O where M is Ni or Co, A is a mono carboxylic anion of the form RCOO where
R is CaHa*! and n-O-5, and x and m are numbers satisfying the following conditions: 0.2 < -x < - 0.4, 0.0 < -m < - 4. It is made
by starting with a synthesis mixture having Ni or Co (divalent cation) to aluminum (divalent cation) molar ratio between 1:1 and 10:1,
mono carboxylic anion to aluminum (divalent cation) molar ratio between 0.1:1 to 1.2:1 and optionally added other anions. The process'
comprises of reacting a mixture comprising nickel (or cobalt) and aluminum cations and mono carboxylic anions in an aqueous slurry at a
temperature of at least 40 °C and a pH of at least 7.

FOR THE PURPOSES OF INFORMATION ONLY

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WO 96/29282

PCT/US96/0J257

NICKEL AND COBALT CONTAINING HYDROTALCITE-LIKE
MATERIALS HAVING A SHEET-LIKE
MORPHOLOGY AND PROCESS FOR PRODUCTION THEREOF

Related Application

This is a continuation-in-part of our
co-pending application Serial No. 085,804, filed
July 6, 1993, entitled "Hydrotal cite- like Materials
Having a Sheet-like Morphology and Process for
Production Thereof".

Technical Field

This invention relates to nickel and
cobalt containing hydrotalcite-like compounds having
a unique sheet like morphology, defined as broad and
thin crystals having a breadth to thickness ratio of
more than 50 and to a process for the production
thereof. These hydrotalcite-like materials have
applications in new fields as well as conventional
applications, arising from their unique sheet
crystal morphology and derived physico-chemical
properties .

Background of the Invention

Hydrotalcite is a naturally occurring
mineral having the formula:

Mg 6 Al 2 (OH) 16 C0 3 .4H 2 0

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Several other cation pairs forming
hydrotalcite-like structure also occur in nature and
of particular interest for the purposes of the
present invention is takovite, the nickel analog of
hydrotalcite having the formula:

Ni 6 Al 2 (OH) 16 C0 3 .4H 2 0

Hydrotalcite-like materials or anionic
clay minerals have similar structures and have the
general formula:

[M II 1 _ x M III x ](OH) 2 . X / y A y- . mH 2 0

where M 11 and M 111 are divalent and trivalent
cations, respectively, and A is an anion. These
materials belong to the pyroaurite-sjogrenite class
of minerals and their crystal structure has been
described in the literature (Allmann, R., Acta
Cryst. (1968), B24, 972). They have been widely
described in the literature (Cavani et al.,
-Catalysis Today", 11, 173(1991) and references
therein). Although, the word hydrotalcite refers
specifically to the Mg-Al mineral, in the catalyst
literature, it encompasses all the materials in the
pyroaurite-sjogrenite class. Hence for the purposes
of this invention, the term hydrotalcite will
include materials containing nickel or cobalt and
aluminum. The most common approach to synthesis of
nickel (or cobalt) hydrotalcites is by
coprecipitation of the two cations under conditions
of supersaturation (U.S. Patents 3,896,053,

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3,941,721, 4,105,591, 4,298,766) and references
therein* It is well known that hydrotalcites
prepared by the above procedures have a hexagonal
plate-like crystal habit (Reichle, W. T. , Chemtech,
1986, 58). When crystallized at room temperature
the crystallites have a diameter of approximately of
about 0.01 to 0.1 microns and can be grown to about
1 to 5 microns by hydrothermal treatment. In all
cases, the ratio defined by the diameter to the
thickness of hexagonal crystals in such synthetic
materials of the prior art are in the range of about
5 to about 20. Scanning and transmission electron
microscope (TEM) pictures of hydrotalcite with the
hexagonal plate-like crystal morphology are shown in
Figures la and lb, respectively.

The term M hydrotalcite- like" is recognized
in the art. It is defined and used in a manner
consistent with usage herein in the comprehensive
literature survey of the above-referenced Cavani et
al article.

Summary of the Invention

We worked on synthesizing nickel (or
cobalt) containing hydrotalcites using variations in
the nickel or cobalt and aluminum compounds and more
importantly, with mono carboxylic organic acids such
as formic, acetic, propionic and isobutyric, having
the following formula:

M l-x Al x t 0H > 2+x-y-nz:y A ~ ' ** n ~**2°
where M is either Mi or Co, A~ is a mono carboxylic

anion, B is OH or an optionally added anion or a

combination of anions, x, y, z and m are numbers

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satisfying the following conditions:

0.2 < x <- 0.4

0.1 < y <- 0.5

0 < z <- 0.4

0 <-m <- 4.0

1 <-n <» 3

From the above it will be seen that, where
B is not present, (where z-0), the basic formula of
our materials is M^Al^OH^.xA" .mHjO. The mono
carboxylic anion A" may be substituted by one or
more different anions having an average valence of
n, up to about 90 mole percent. We discovered that
hydrotalcite-like materials with a sheet-like
morphology (hereafter referred to as "sheet
hydrotalcites") are generally crystallized when
monocarboxylic anions are used, for balancing the
positively charged hydroxide structure, in the
synthesis. Electron microscope photographs of the
new materials are shown in Figures 2a, 2b, 3a and
3b. Interestingly dicarboxylic acids and other
polycarboxylic acid compounds will not operate to
make the sheet hydrotalcite-like materials of our
invention.

It was also found that such new crystal
morphology could also be formed when nickel (or
cobalt) was partially (up to about 50 mole percent)
substituted from a family of cations consisting
essentially of Mg, Ni, Co, Zn, Cu, Mn? and aluminum
was partially (up to about 50 mole percent)
substituted from a family of cations consisting

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essentially of Cr and Fe. After one sheet material
is made, a portion of the anions may be exchanged
for other anions.

It has been found that the sheet
hydrotalcite has several useful characteristics
arising from the sheet crystal habit. In contrast
to typical hydrotalcite materials, having the
hexagonal plate-like crystal morphology, the new
sheet material can be shaped or formed without
binders into shapes which retain their mechanical
strength even after calcination to high temperature.

It is the object of the present invention
therefore to provide novel sheet hydrotalcite
materials.

It is also the object of this invention to
provide a process for producing the sheet
hydrotalcites in a commercially advantageous manner.

Description of the Drawings

Figure la is the scanning electron
microscope picture of a conventional hexagonal
nickel hydrotalcite known in prior art taken at
20,000 X (Comparative Example 1).

Figure lb is the transmission electron
microscope picture of the same hydrotalcite taken at
41,000 X.

Figure 2a is the scanning electron
microscope picture of the sheet nickel-hydrotalcite
produced according to this invention using acetic
acid taken at 1800 X (Example 1).

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Pigure 2b is a transmission electron
microscope picture of the sheet nickel-hydrotalcite
produced according to this invention using acetic
acid taken at 50,000 X (Example 1).

Figure 3a is a scanning electron
microscope picture of the sheet cobalt-hydrotalcite
produced according to this invention using acetic
acid taken at 3000 X (Example 6).

Figure 3b is a transmission electron
microscope picture of the sheet cobalt-hydrotalcite
produced according to this invention using acetic
acid taken at 50,000 X (Example 6).

Detailed Description of the Invention

A comparison of Figures la with 2a and 3a
shows that the nickel (or cobalt) hydrotalcite of
this invention differs from the conventional
hydrotalcite having a hexagonal plate-like
structure. As seen from Figure 2a, the longitudinal
dimension of the sheet is much larger than the
thickness. The ratio is so large that the sheets
are pliable and are crumpled. The longitudinal
dimensions of the sheets can be relatively
accurately measured from SEM pictures (Figures 2a,
3a). As seen from Figure 2a, the ratio of the
maximum longitudinal dimension to the minimum
longitudinal dimension is less than 5. More often
the ratio is very close to unity. In the discussion
which follows the breadth of the sheets will refer
to the maximum longitudinal dimension. The breadth
was calculated by averaging the maximum longitudinal
dimension of at least ten different sheet

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crystallites. The sheet hydrotalcite of the present
invention has sheets where the breadth ranges from
about 5-500 microns.

The thickness of the sheets is estimated
from the specific surface area and the density. The
thickness of the sheets is calculated from the
following equation:

thickness «= 2

surface area x density

where the surface area is measured by BET method and
the density of the hydrotalcite-like materials can
be calculated for different cation pairs and anions
by crystal lographic means. The skeletal densities
calculated for hydrotalcite-like material having the
Ni (or Co), Al cation pair in a molar ratio of 2.0:1
of M/Al, where M is Ni or Co, dried ovemite at
60 °C, with different anions in the interlayer, are
listed in the table below.

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Skeletal Densities of Different
Hvdrotalcite-Like M aterials fg/cc)

Ni-Al- formic

2.61

Ni-Al-acetic

2.25

Ni-Al-propionic

1.73

Ni-Al-isobutyric

1.62

Co- Al- formic

2.61

Co-Al-acetic

2.25

Co-Al-propionic

1.73

Co-Al- i sobutyr ic

1.62

Based on the above formula, the thickness
of the sheet hydrotalcite-like material of the
present invention is calculated to be about 0.005 to
0.1 microns. Therefore the ratio of breadth to
thickness of the sheet hydrotalcite-like materials
of the present invention is at least 50, generally
up to about 5000, and more typically of the order of
500-1500.

The sheet hydrotalcites of the present
invention are made by contacting an aluminum
compound with a nickel (or cobalt) compound in
water, together with a carboxylic acid having up to
6 carbon atoms. The aluminum source can be in the
form of a reactive oxide, hydroxide, anionic salt or
a mono carboxylic acid salt, the preferred source of
aluminum being sodium aluminate or pseudoboehmite
with pseudoboehmite being the most preferred.

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Inorganic salts of the trivalent cation, e.g.
aluminum nitrates, are not preferred for use as a
source for the present invention. The nickel (or
cobalt) source may be in the form of oxide,
hydroxide or a mono carboxylic acid salt, the most
preferred source being the hydroxide. Inorganic
salts of the divalent cation, e.g. nickel (or
cobalt) nitrate are not preferred for use as a
source for the present invention. The nickel (or
cobalt) source is added such that the molar ratio of
divalent to trivalent metal is about 1:1 to 10:1;
preferably between 2:1 and 4:1. The amount of water
soluble mono carboxylic acid equivalents is added
such that the ratio of organic acid anion to
trivalent cation is preferably 1:1 on a molar basis
but may vary from 0.1:1 to 1.2:1. In cases where
the ratio is less than unity the rest of the charge
is balanced by hydroxyl anions present in the
synthesis medium. Optionally, an inorganic anion or
a combination of inorganic anions may also be
present in the synthesis mixture, in which case they
are incorporated into the layers instead of the
hydroxyl ions. In any case it is preferred for the
purposes of the present invention that at least 10
mole percent of the anions in the synthesis mixture
be monocarboxylic anions. The mono carboxylic acid
equivalents are added either in the form of the acid
or as salts of any of the combination of cations
being used. The final pH of the synthesis mixture
should be between 7 and 12 but preferably between 8
and 9. Heating and mixing the above reaction
mixture will facilitate the crystallization

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reaction. The reaction time can extend from 0.5 h
to several hours, i.e. as much as 72 h or more
depending on the reaction temperature and mixing.
The crystallization is carried out at a temperature
of at least 40°C and atmospheric pressure. The rate
of crystallization can be accelerated by increasing
the temperature. The synthesis can also be carried
out at higher than atmospheric pressures in a closed
system, in which case the temperature can exceed
100°C and the time of reaction is further shortened.
The preferred crystallization temperature is about
60 to 100°C but more preferably between 85 and 95°C
and at atmospheric pressure. After the
crystallization period, the product consists of a
thick homogeneous slurry.

It was also discovered that the
hydrotalcites of the present invention could also be
synthesized starting from the hexagonal
hydrotalcites. It is known in the literature that
calcined hydrotal cite- like materials have the
capacity to reconstitute the original layered
structure upon exposure to water (U.S. Patent
5,079,203). The temperature of calcination is
critical and should not exceed 500-C. We discovered
that if the calcined hexagonal hydrotalcite-like
material is recrystallized in a aqueous solution
containing a monocarboxylic organic anion of the
form RCOO-, where R is C n H 2n+1 and n is an integer
from 0 to 5, sheet hydrotalcite-like material is
reconstituted. This route provides a method of
transforming the hexagonal hydrotalcite made by
other methods to the sheet hydrotalcite-like
material of the present invention.

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lt is clear from the present invention
that the presence of a water soluble mono carboxylic
anion is the key in the synthesis of sheet
hydrotalcite.

A dried sample of the slurry shows an
X-ray diffraction pattern characteristic to
hydrotalcite materials but with expanded d-spacing
due to the larger size of the intercalated organic
anions. Typical X-ray diffraction lines of a
crystalline sheet hydrotalcite made with acetic
acid have been identified and are shown in Table 1.

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Table 1

Powder diffraction pattern of sheet hydrotalcite
synthesized in Example 1 dried at room temperature.
Spacings in A.

d spacing

Relative

Miller

IA1

Intensity

Indices

12.50

100

0,0,3

6.46

0,0,6

4.22

0,0,9

3.08

0,0,12

2.57

0,1,5

2.36

0,1,8

1.51

1,1,6 or 1,1,0

The cry stall inity of the material can vary
depending on the reaction temperature, time and
mixing. Most of the sheet hydrotalcites , according
to this invention, show diffraction patterns with
strong 001 lines and weak and sometimes ill-defined
hkO lines. Again this is the result of the unique
morphology of the crystals. An easy
characterization of crystallinity consists of
depositing a few drops of synthesis suspension on a
glass slide, drying and analyzing by X-ray
diffraction. As commonly used with layered
structures, this method orients the crystals and
enhances the 001 lines. Several d(003) spacings,
obtained with different mono carboxylate anions are
shown in Table 2. Samples for scanning electron
microscopy were prepared by freeze drying the slurry
to prevent the rolling up of sheets as would
normally occur in a regular drying process.

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Table 2

d(003) spacings for several sheet hydro talc ites made
with different organic acids and dried at 60°C.

Carboxvlic Anion df003) Spacing Example

o
A

Formic 7.64 1

Acetic 12.3 2

Propionic 13.02 3

Isobutyric 15.15 4

Example 1

15.5 g of pseudoboehmite (Versal 850) was
slurried in 500 ml of deionired water. 13.7 g of
acetic acid was added to the slurry The suspension
was vigorously agitated and heated to 50-60°C for
0.5 h. Then 40.9 g of nickel hydroxide along with
1.5 1 of deionized water were added to the resulting
mixture and heated to 85-95°C for 6 hours. The
ratio of nickel to aluminum in the mixture was 2:1
and the ratio of carboxylic anion to aluminum was
1:1. A portion of the final slurry was dried at
60°C and X-ray diffraction carried out to confirm
the hydrotalcite phase. TEM was performed on
another portion of the slurry to confirm the
presence of sheet hydrotalcite (Figure 2b). Surface
area of a sample dried and conditioned at 150°C was
about 35 m2/g, which corresponds , using the
relationship described above, to about 0.02 micron

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in thickness. The average breadth of the sheets was
determined from SBM pictures (Figure 2a) to be 20
microns, yielding a ratio of breadth to thickness of
1000.

eompara1 -™» Example 1

A mixture of 20.6 g of aluminum nitrate
and 32.15 g of nickel nitrate were dissolved in
300 ml of deionized water. A separate solution of
10.15 g sodium hydroxide pellets dissolved in 500 cc
of DI water was prepared. The two solutions were
coprecipitated at a constant pH of 9.0 with vigorous
stirring. Upon completion of addition the slurry
was heated to 80*C for 16 h. After cooling the
slurry was washed to remove the excess salt. The
procedure described above substantially follows the
description in the prior art for making nickel
hydrotalcite. A portion of the final slurry was
dried at 60»C and X-ray diffraction carried out to
confirm the hydrotalcite phase. The TEM pictures
clearly show the hexagonal crystallites (Pigure lb).
The SEM pictures distinctly show clustered,
individual platelets which are approximately 0.5
micron in diameter (Figure la).

Example 2

~~~~ 14.9 g of pseudoboehmite (Versal 850) was

slurried in 500 ml of deionized water. 19.3 g of
isobutyric acid was added to the slurry. The
suspension was vigorously agitated and heated to
50-60 °C for 0.5 hour. Then 40.8 g of nickel
hydroxide along with 1.5 1 of deionized water were

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added to the resulting mixture and heated to 85-95°C
for 6 hours. The ratio of nickel to aluminum in the
mixture was 2:1 and the ratio of carboxylic anion to
aluminum was 1:1. A portion of the final slurry was
dried and the presence of hydrotalcite-like phase
confirmed by X-ray diffraction. Another portion of
the final slurry was freeze dried and the sheet
morphology confirmed by SEM. Transmission electron
microscopy also shows the presence of sheet
hydrotalcite-like material.

Example 3

15 g of pseudoboehmite (Versal 850) was
slurried in 500 ml of deionized water. 13.7 g of
acetic acid was added to the slurry. Then 61.3 g
nickel hydroxide along with 1.5 1 of deionized water
were added to the resulting mixture and heated to
85-95 p C for 6 hours. The ratio of nickel to
aluminum in the mixture was 3:1 and the ratio of
carboxylic anion to aluminum was 1:1. A portion of
the final slurry was dried and the presence of
hydrotalcite-like phase confirmed by X-ray
diffraction. Another portion of the final slurry
was freeze dried and the sheet morphology confirmed
by SEM.

Example 4

15.13 g of pseudoboehmite (Versal 850) was
slurried in 500 ml of deionized water. 13.7 g of
acetic acid was added to the slurry. The suspension
was vigorously agitated and heated to 50-60 °C for
0.5 h. 61.7 g nickel hydroxide along with

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1.5 1 of deionized water were added to the resulting
mixture and heated to 85-95°C for 6 hours. The
ratio of nickel to aluminum in the mixture is 4:1
and the ratio of carboxylic anion to aluminum is
1:1. A portion of the final slurry was dried and
the presence of hydrotalcite-like phase confirmed by
X-ray diffraction. Another portion of the final
slurry was freeze dried and the sheet morphology
confirmed by SEM.

Example 5

15.13 g of pseudoboehmite (Versal 850) was
slurried in 500 ml of deionized water. 16.3 g of
propionic acid was added to the slurry. The
suspension was vigorously agitated and heated to
50-60°C for 0.5 fa. 40.8 g nickel hydroxide along
with 1.5 1 of deionized water were added to the
mixture and heated to 85-95'C for 6 hours. The
ratio of nickel to aluminum in the mixture is 2:1
and the ratio of carboxylic anion to aluminum is
1:1. A portion of the final slurry was dried and
the presence of hydrotalcite-like phase confirmed by
X-ray diffraction. Another portion of the final
slurry was freeze dried and the sheet morphology
confirmed by SEM.

Example 6

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de ionized water were added to the resulting mixture
and heated to 85-95°C for 6 hours. The ratio of
cobalt to aluminum in the mixture is 2:1 and the
ratio of carboxylic anion to aluminum is 1:1. A
portion of the final slurry was dried and the
presence of hydrotalcite-like phase confirmed by
X-ray diffraction. TEM was performed on a portion
of the slurry to confirm the presence of sheet
hydrotalcites (Figure 3b). Another portion of the
slurry was freeze dried and SEN used to determine
the average breadth which was 25 micron (Figure 3a).
The surface area of the freeze dried sample,
conditioned at 150°C was 40 m2/g corresponding to a
thickness of 0.02 micron, yielding a breadth to
thickness ratio of 1250.

Example 7

15.1 g of pseudoboehmite (Versal 850) was
slurried in 500 ml of deionized water at 60°C for
0.5 h. 13.7 g of glacial acetic acid was added to
the slurry. 30.7 g of nickel hydroxide and 6.4 g of
magnesium hydroxide were added along with 1.5 1 of
deionized water. The mixture was heated to 95 *C for
6 hours. The ratio of the divalent cation to
aluminum in the slurry is 2:1 and the ratio of
carboxylic anion to aluminum is 1.0. 25% of the
divalent cation was magnesium the rest being nickel.
A portion of the final slurry was dried and the
presence of hydrotalcite-like phase confirmed by
X-ray diffraction. Another portion of the final
slurry was freeze dried and the presence of a unique
sheet morphology was confirmed by SEM.

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gXMBPle 8

15 g of pseudoboebmite (Versal 850) was

slurried in 500 ml of deionised water. 7.92 g of
acetic acid was added to the slurry. «>e suspension
was vigorously agitated and heated to 50-60*C for
0.5 hour; 40.7 g of cobalt hydroxide along with
1 5 1 of deionised water were added to the resulting
mixture and heated to 85-95'C for 6 hours. The
molar ratio of cobalt to aluminum in the mixture was
2-1 and the ratio of carboxylic acid to aluminum was
0.6:1. A portion of the final slurry was dried and
the presence of the hydrotalcite-like phase
confirmed by X-ray diffraction. Another portion of
the final slurry was freeze dried and the sheet
morphology confirmed by SEM.

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Claims

1. Hydrotalcite-like material in the form
of sheets, said sheets having an average broadness
to thickness ratio of about 50:1 to about 5000:1,
and having the following formula:

(M 1 _ at Al x )(0H) 2 • • mH 2 0

where M is Ni or Co, A" is a mono carboxylic anion
of the form RCOO~ where R is C n H 2n+1 and n»0-5, x is
a number between 0*2 and 0.4 and m a number between
0 and 4.

2. The hydrotalcite-like material of
claim 1 wherein M is substituted up to about 50 mole
percent by divalent cations selected from the group
consisting of Mg, Ni, Cu, Zn, Co, Mn.

3. The hydrotalcite-like material of
claim 1 wherein Al is substituted up to about 50
mole percent by trivalent cations selected from the
group consisting of Cr and Fe.

4. The hydrotalcite-like material of
claim 1 wherein the sheet broadness to thickness
ratio is about 100:1 to about 2000:1.

5. The hydrotalcite-like material of
claim 1 wherein the sheet broadness to thickness
ratio is about 500-1500.

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PCTAJS96/03257

6. The hydrotalcite-like material of
claim 1 where n = 0.

7. The hydrotalcite-like material of
claim 1 where n - 1.

8. The hydrotalcite-like material of
claim 1 where n « 2.

9. The hydrotalcite-like material of
claim 1 where n " 3.

10. The hydrotalcite-like material of
claim 1 where n - 4.

11. The hydrotalcite-like material of
claim 1 where n - 5.

12. A process for producing hydrotalcite-
like material having a sheet like morphology and
having an average broadness to thickness ratio
ranging from 50 to 5000 and having the following
formula:

(M 1 _ X A1 X )(0H) 2 • xA . mH 2 0

where M is Ni or Co, A is a mono carbotacylic anion of
the form RCOO", where R is of the formula C n H 2n+ l
and n-0-5, x is a number ranging between 0.2 and 0.4
and m is a number between 0 and 4, said process
comprising reacting a mixture of divalent metal
cations comprising at least 50 mole percent

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( Claim 12 cont'd)

nickel or cobalt cations and trivalent metal cations
comprising at least 50 mole percent aluminum
cations, said divalent metal cations and trivalent
metal cations being present in a ratio of about 1:1
to about 10:1 with mono carboxylic anion having 1-6
carbon atoms, in an aqueous slurry at a temperature
of at least 40°C, at a pH from 7 to about 12, and at
a ratio of mono carboxylic anion to trivalent metal
cation is about 0*1 to about 1.2:1, followed by
drying said slurry at a temperature of at least 40°C
to crystallize a hydrotalcite-like material having a
sheet-like morphology and having an average
broadness to thickness ratio ranging from 50 to
5000.

13. Process of claim 12 wherein the ratio
of mono carboxylic anion to trivalent cation is
about 0.6:1 to about 1.2:1.

14. The process of claim 12 where
nickel hydroxide is the source of nickel.

15. The process of claim 12 where a mono
carboxylic salt of nickel is the source of nickel
and the mono carboxylic anion.

16. The process of claim 12 wherein
acetic acid comprises a source of the mono
carboxylic anion.

WO 96/29282

-22-

PCT/US96/03257

17. The process of claim 12 where
pseudoboebmite is the source of aluminum.

18. The process of claim 12 where sodium
aluminate is the source of aluminum.

19. Process of claim 12 wherein the ratio
of divalent metal cations to trivalent metal cations
is about 2:1 to about 4:1.

20. A process wherein nickel containing
hydrotalcitellike material with hexagonal morphology
is calcined between 300 and 550'C and is thereafter
used as a source of nickel and aluminum cations in a
process of claim 12.

21 A process wherein cobalt containing
hydrotalcitellike material with hexagonal morphology
is calcined between 300 and 550'C and is thereafter
used as a source of cobalt and aluminum cations in a
process of claim 12.

22 Process of claim 12 wherein the
crystallization temperature is about 60 to 100-C.

23. Process of claim 12 wherein the
crystallization temperature is about 85 to 95*C.

WO 96/29282 PCT/US96/03257

1/6

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3/6

PCT/US96/0J257

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PCT/US96/032S7

INTERNATIONAL SEARCH REPORT

International application No.
PCT/US96703257

A. CLASSIFICATION OF SUBJECT MATTER

IPC(6) :C01B 31/30

US CL : 423/420.2; 556728, 31

onal classification and IPC

According to International Patent Classification (IPC) or to both nati

B. FIELDS SEARCHED

Minimum documentation searched (classification system followed by classification symbols)
U.S. : 423/420.2; 556728, 31

Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched
NONE

Electronic data base consulted during the international search (name of data base and, where practicable, search terms used)
NONE

C. DOCUMENTS CONSIDERED TO BE RELEVANT

Category*

Citation of document, with indication, where appropriate, of the relevant passages

Relevant lo claim No.

A
P

US.A. 4,458,026 (REICHLE) 03 JULY 1984, See col. 3, line
6 to col. 4, line 24.

US.A, 5,399,329 (SCHUTZetal) 21 MARCH 1995, See col.
8, line 25 to col. 10, line 23.

1-16

F | Further documenu are listed in the continuation of Box C. Q See patent family annex.

document defe
tobcof partk*

•E-
•L"

ate of the ut which m oot coaeidcrcd

o or after the mleraetioneJ filinj dele
doubts on priority clairo(s) or which it

IB Of 1

document pubbshed after the ntemeUoneJ filinf date or priority
■nd do* in conflict with the application but cited to uoderitand the
or theory undcrrying the invention

of particular relevance; the churned mvenUoo
cannot be considered lo involve an

document published prior to the inirrmboaaJ film* d*ic but kirr than

obvioualoapciaon
of the i

mine art
family

Date of the actual completion of the international search
24 MAY 1996

Date of mailing of the international search report

t 8 JUL 1996

Name and mailing address of the ISA/US
Commissioner of Patent* and Trademarks

Washington, D.C. 20231
Facsimile No. (703) 305-3230

Authorized officer /\^^_^J^ £g

WAYNE A. LANGEL

Telephone No. (703) 308-0248

Form PCT71SA/210 (second sheet)(July 1992)*

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